The present invention relates to a pitch system for a wind energy system and a method for operating a pitch system.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
In wind energy systems, a pitch angle can be set by a pitch system according to the wind forces acting on the rotor blade during operation and, in this way, a drive torque for an electric generator of the wind energy system can be regulated. For this purpose, the pitch angles required are fed to the pitch system by means of a corresponding control signal from a generator control system. This generator control system is also referred to as a turbine control system.
An electrical pitch system may include an emergency energy store which is dimensioned according to an energy requirement in order to move a rotor blade into a safety position (by an “emergency maneuver”) in the event of the failure of the external energy supply and thus safely to brake the wind energy system. It is usual, in this process, to move to the feathered position, in which a blade plane of the rotor blade is arranged perpendicular to the plane of rotation of the rotor blades.
The emergency energy store may include double layer capacitors. These age over their operating life and thereby lose capacitance. For this reason, monitoring and regular testing of the emergency energy store is necessary in order to be able to ensure the functioning of the emergency maneuver and to determine the point at which the store needs to be replaced.
A disadvantage of the conventional solutions is that, for testing an emergency energy store, relatively expensive electrical test circuits are needed and the testing takes time, during which the wind energy system cannot be used for generating electrical energy.
It would therefore be desirable and advantageous to obviate prior art shortcomings and to provide an improved method and system in order to ensure reliable operation of a wind energy system while simultaneously ensuring a high degree of availability of said system.